Process for the preparation of anhydro bases from cyclammonium quaternary salts



PROCESSFOR THE PREPARATION OF- ANHYDRO BASES FROM CYCLAMMONIUM QUATERNARY SALTS Robert M. Lindquist, Vestal, N.Y.

N Drawing. Application September 25, 1956 Serial No.-.612,065

3 Claims. .,(Cl. 260-240) This inventionrelates to'anhydro bases-and particularly to a process forthe preparation of said bases from cyclammonium quaternary salts The anhydro bases of this invention are represented by-the following general formula:

wherein R represents an aliphatic group such as an alkyl group, i.e., methyl, ethyl, n-propyl, n-butyl, isobutyl, allyl, alkoxyalkyl, i.e., fi-ethoxyethyl, hydroxyalkyl, i.e.,

,B-hydroxyethyl, carboxyalkyl, i.e., carboxymethyl, carboxyethyl, aralkyl, i.e., benzyl, phenethyl, etc aryl, i.e., phenyl, naphthyl, n represents a positive integer of from 1 to 2, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 members, i.e., nuclei of 'the'-.oxazole series, such as 4- methyloxazole, 4-phenyloxazole, S-methyloxazole, etc., nuclei of the benzoxazole series, such as benzoxazole, 5-

chlorobenzoxazole, S-phenylbenzoxazole, S-methylbenzene, arylalkylmethylene, i.e., benzylmethylene, arylmeth-i ylene, i.e.,.phenylmethylene,.diarylmethylene, i.e, diphenylmethylene, etc. When m is equal to 2, .3 0114, then Y represents a divalent arylimino group, i.e., phenylimino,

p-chlorophenylimino, o-rnethoxyphenylimino,v m-bromophenylimino, 0-, p-, and m-tolylimino, p-nithrophenyli-' mino, 00- and. [3- naphthylimino,. etc.

It has been proposed to prepare anhydro bases of the type represented by general Formula I, by treating cyclammonium quaternary-salts with strong bases such as triethylamine or sodium hydroxide in order to abstract the elements HX as representedin the following general scheme:

The usual priorart procedure consists in treating an aqueous..solution ,of va cyclarnmonium quaternary salt with strong alkali to obtain the anhydro base either..as.

a solid or a liquid. If the anhydro base is highlyinsoluble in the reaction mixture, it was isolated by filtration. If, however, the solid was highly soluble in such mixture, or is in the form of a liquid, it was isolated by extracting said base from the reaction mixture with a Water immiscible solvent. Thus, Vongerichten and Hof- 2,891,950 Patented June. 23,, ,1959

chen, Ben, 1908, 41, 3054, treated quinaldine-ethiodide, with aqueous KOH and obtained an oil which they regarded as having the following structurer.

(III) Such compounds, resultingfrom the elimination -of.HXl from methyl cyclammonium.heterocycliequaternary salts, were called methylene bases- A.more recentarticleby Hamer, J. Chem. Soc., 1947 954359,- describesothen anhydro bases and their derivativesas well as improved methods of synthesis.

One of the main objections/to the previousmethods. of making anhydro bases is the. deleteriousefiect ofthe... strong alkali employed. Many.oftheanhydrobasesare very sensitive compounds and ...undergo.decomposition. in the presenceof strong alkali, and makes it difficultrto isolate in pure form while. ensuring. good yields...

Since the anhydro bases .-and-their derivatives. arouse-\- ful intermediates in sensitizing dye syntheses, particularly where milder reactionconditions are. required,.,an..im-.. proved method of producing said bases has long. been .in... demand.

It is to be pointed out. that, ordinarily,, said,.bases,..are.1 notused as such .in sensitizing dye synthesesowing to-the... inconvenience of their separate. preparation. ,Instead,... they are prepared in situ in the course ,ofthesensitizing dye syntheses by the addition,.of-.,basic catalysts...

It is an object of this invention to provide a general method for the facile preparation of anhydro bases of cyclamrnonium heterocyclic quaternary salts which eliminates the deleterious effects of strong alkalis;

Anotherobject of this inventionis to provide said L bases. in an isolated condition for use in" sensitizing-dye... syntheses so that such syntheses can be carried out under. milder reaction conditions and with'ifewer byproducts.

We have found that when a solution .of a cyclam-, monium quaternarysalt .is passed through acolumn packed with an anion-exchange resin. which has been re-,. generated to its hydroxide form, the elements HX (where H is hydrogen and X is the anion of the quaternary salt), are removed fromv thelquaternary salt by theresin, and. the methylene baseor its equivalent passes on throughthe column and is obtained in pure form in the, efl1uent,l iquor from the column. In this method, themethylenebaseis in contact with the alkaline OH. groups of the ionexchange resin for a very short interval so that any side reactions due to the action of alkali are eliminated An alternate procedure is to stir a solution of a eyelammonium quaternary salt-with OHeUf-m Ore fPOItlOllSff of an anion-exchange-resinwhich has been regenerated} to its hydroxide form, until'the'elements =of HX(where H is hydrogen and-X is the anion of the qua-ternary-salt.)'- have been completely removediromthe-quaternarysalt by the resin. This point may be ascertained by -testing the solution for the presence of the'anion-X. The resin can then be removed by filtrationto give a solution of 1-- the methylene base. v

A generalized formulation for the-involvedreaction-" is as follows:

wherein Z, R, X, Y, m and n have the values shown above.

The term anhydro base as used herein is defined in The Organic Chemistry of Nitrogen, 1937 (Taylor and Baker).

The anion exchange resins contemplated herein are highly basic resinous quaternary ammonium bases or salts thereof. The starting material for the aforementioned highly basic anion exchange resins may be the well-known weakly basis anion exchange resins containing amino groups. They are made, for example, by reacting a phenol-aldehyde condensate with formaldehyde and a secondary amine, or an aliphatic polyamine according to the disclosures of U.S. Patent, 2,732,352 or by condensing a phenylenediamine with formaldehyde, followed by alkylation to convert primary and secondary amino groups to tertiary amino groups and quaternizing such amino groups with alkyl halides as disclosed in U.S. Patent 2,732,352.

Alternately, the highly basic anion exchange resins may be prepared by halomethylating a cross-linked insoluble copolymer of a monovinyl hydrocarbon such as styrene and then aminating the halomethylated co polymer by reaction with a tertiary amine followed by conversion of the resulting resinous quaternary salt to the highly basic hydroxide form by treating said resinous quaternary salt with an alkali such as sodium hydroxide as disclosed in U.S. Patent 2,591,573.

The anion exchange resin employed in the present application is a type sold on the market under the trade name Amberlite IRA-400 by the Rohm and Haas Company, said Amberlite IRA400 being dispensed in the form of a quaternary halide, i.e., chloride, and may be regenerated to the hydroxide form by treatment with dilute alkali such as sodium hydroxide.

The invention is further illustrated by the following examples but is not restricted thereto.

Example I A solution of 1 gram of 3-ethyl-2-methylbenzoxazolium iodide in 50 mls. of methanol was passed through a column packed with 20 mls. of regenerated Amberlite IRA400 (regenerated with 4% aqueous sodium hydroxide, washed neutral with water and Washed with methanol) and was followed by an afterwash of 50 mls. of methanol. The efiluent liquor gave a negative Beilstein test for halogen. Evaporation of a small portion of the efiiuent liquor left a yellow gum which was soluble in ether and which was insoluble in water. A test portion of the effluent liquor coupled readily with 2(8- acetanilidovinyl)-3-ethylbenzoxazolium iodide on boiling and the addition of a few crystals of sodium acetate. The starting material did not couple readily under these conditions.

Example 11 A solution of 1 gram of 3-ethyl-Z-methylbenzothiazolium iodide in 50 mls. of methanol was passed through a column packed with 20 mls. of regenerated Amberlite IRA-400 (regenerated with 4% aqueous sodium hydroxide, washed neutral with water, and washed with methanol) and was followed by an afterwash of 50 mls. of methanol. The effluent liquor gave a negative Beilstein test for halogen. Evaporation of a small portion of the eflluent liquor left a residue which was soluble in ether and which was insoluble in water. A test portion of the efiluent liquor coupled readily with 2-(fi-acetanilidovinyl)-3-ethylbenzoxazolium iodide at room temperature with no catalyst.

Example III A solution of 28.8 grams of 3-carbethoxymethyl-2- methyl benzothiazolium bromide in 300 mls. of methanol was passed through a column packed with 150 mls. of

regenerated Amberlite IRA-400 (regenerated with 4% aqueous sodium hydroxide, washed neutral with Water,

and washed with methanol) and was followed by an after- 5 wash of 250 mls. of methanol. The eflluent liquor gave a negative Beilstein test for halogen. A small portion of the efiiuent liquor was evaporated to a gum which was soluble in ether and which was insoluble in water. A test portion of the efiluent liquor coupled with 2-(fiacetanilidovinyl) -3-ethy1benzoxazolium iodide immediately at room temperature with no catalyst.

Example IV A solution of 2 grams of ,8-(4-chloro)-anilino-;8-ethylvinyl-3-ethyl-5,6-dimethylbenzoxazolium iodide in 50 mls. of methanol was passed through a column packed in mls. of regenerated Amberlite IRA40() (regenerated with 4% aqueous sodium hydroxide, Washed neutral with water, and washed with methanol) and was followed by 20 an afterwash of 50 mls. of methanol. A portion of the effiuent liquor was diluted with water and was acidified with dilute nitric acid. Addition of silver nitrate solution to this solution gave no precipitate. The eflluent liquor was evaporated to give an amorphous yellow powder which weighed 1.4 grams. The melting point was 45-49 C. The product was soluble in ether and was insoluble in Water.

I claim:

1. A process of preparing anhydro bases which comprises treating With an ion exchange resin regenerated to its hydroxide form, a cyclammonium salt selected from the class consisting of those of the following formulae:

H 6' e i a E /N R X and /Z\ H I C C(OH=CH)m-1A wherein Z represents the atoms necessary to complete a benzoxazole nucleus, R is selected from the class consisting of lower alkyl and carb lower alkoxy lower alkyl, X is an anion, Y is alkylene, m is a whole ntunber from 2 to 4, A is a divalent arylimino group selected from the class consisting of those of the benzene and naphthalene series and H is hydrogen.

2. The process of preparing an anhydro base which comprises treating with an ion exchange resin regenerated to its hydroxide form 3-ethyl-Z-methylbenzoxazolium iodide.

3. The process of preparing an anhydro base which comprises treating with an ion exchange resin regenerated to its hydroxide form B-(4-chloro)-anilino-,8-ethylvinyl-3- ethyl-5,6-dimethylbcnzoxazolium iodide.

References Cited in the file of this patent UNITED STATES PATENTS 2,484,536 Straete Oct. 11, 1949 2,635,061 McBurney Apr. 14, 1953 OTHER REFERENCES Kressman: Research, May 1952, pp. 212-219. Chem. and Eng. News, vol. 27, No. 21, p. 1525, May

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,891,950 June 23, 1959 Robert M, Lindquist It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 16, "packed in 20" read packed with 20 Signed and sealed this 10th day of November 1959.,

(SEAL) Attest:

KARL H AXLINE ROBERT C. WATSON Attesiing Oflicer Commissioner of Patents 

1. A PROCESS OF PREPARING ANHYDRO BASES WHICH COMPRISES TREATING WITH AN ION EXCHANGE RESIN REGENERATED TO ITS HYDROXIDE FORM, A CYCLAMMONIUM SALT SELECTED FROM THE CLASS CONSISTING OF THOSE OF THE FOLLOWING FORMULAE
 3. THE PROCESS OF PREPARING AN ANHYDRO BASE WHICH COMPRISES TREATING WITH AN ION EXCHANGE RESIN REGENERATED TO ITS HYDRROXIDE FORM !-(4-CHLORO)-ANILINO-!-ETHYLVINYL-3ETHYL-5,6-DIMETHYLBENZOXAZOLIUM IODIDE. 